#!/bin/bash
#cd /Users/wuchunlong/local/automation-operation-maintenance-scripts/linux/diff 

echo x$(diff a.txt  b.txt)

# [ "x$(diff a.txt  b.txt)" != "x" ]
if [ "x$(diff a.txt  b.txt)" != "x" ]
then 
	echo a.txt  b.txt 文件内容不相同 
else 
	echo a.txt  b.txt 文件内容相同
fi